package cn.com.wxd.wechat.mass.api;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import cn.com.wxd.wechat.common.api.WxErrorExceptionHandler;
import cn.com.wxd.wechat.common.api.WxMessageDuplicateChecker;
import cn.com.wxd.wechat.common.api.WxMessageInMemoryDuplicateChecker;
import cn.com.wxd.wechat.common.session.InternalSession;
import cn.com.wxd.wechat.common.session.InternalSessionManager;
import cn.com.wxd.wechat.common.session.StandardSessionManager;
import cn.com.wxd.wechat.common.session.WxSessionManager;
import cn.com.wxd.wechat.common.util.LogExceptionHandler;
import cn.com.wxd.wechat.mass.bean.WxMpXmlMessage;
import cn.com.wxd.wechat.mass.bean.WxMpXmlOutMessage;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/**
 * <pre>
 * 微信消息路由器，通过代码化的配置，把来自微信的消息交给handler处理
 * 
 * 说明：
 * 1. 配置路由规则时要按照从细到粗的原则，否则可能消息可能会被提前处理
 * 2. 默认情况下消息只会被处理一次，除非使用 {@link WxMpMessageRouterRule#next()}
 * 3. 规则的结束必须用{@link WxMpMessageRouterRule#end()}或者{@link WxMpMessageRouterRule#next()}，否则不会生效
 * 
 * 使用方法：
 * WxMpMessageRouter router = new WxMpMessageRouter();
 * router
 *   .rule()
 *       .msgType("MSG_TYPE").event("EVENT").eventKey("EVENT_KEY").content("CONTENT")
 *       .interceptor(interceptor, ...).handler(handler, ...)
 *   .end()
 *   .rule()
 *       // 另外一个匹配规则
 *   .end()
 * ;
 * 
 * // 将WxXmlMessage交给消息路由器
 * router.route(message);
 * 
 * </pre>
 * @author
 */
public class WxMpMessageRouter {

	protected final Logger log = LoggerFactory.getLogger(WxMpMessageRouter.class);

	private static final int DEFAULT_THREAD_POOL_SIZE = 100;

	private final List<WxMpMessageRouterRule> rules = new ArrayList<WxMpMessageRouterRule>();

	private final WxMpService wxMpService;

	private ExecutorService executorService;

	private WxMessageDuplicateChecker messageDuplicateChecker;

	private WxSessionManager sessionManager;

	private WxErrorExceptionHandler exceptionHandler;

	public WxMpMessageRouter(WxMpService wxMpService) {
		this.wxMpService = wxMpService;
		this.executorService = Executors.newFixedThreadPool(DEFAULT_THREAD_POOL_SIZE);
		this.messageDuplicateChecker = new WxMessageInMemoryDuplicateChecker();
		this.sessionManager = new StandardSessionManager();
		this.exceptionHandler = new LogExceptionHandler();
	}

	/**
	 * <pre>
	 * 设置自定义的 {@link ExecutorService}
	 * 如果不调用该方法，默认使用 Executors.newFixedThreadPool(100)
	 * </pre>
	 * @param executorService
	 */
	public void setExecutorService(ExecutorService executorService) {
		this.executorService = executorService;
	}

	/**
	 * <pre>
	 * 设置自定义的 {@link me.chanjar.weixin.common.api.WxMessageDuplicateChecker}
	 * 如果不调用该方法，默认使用 {@link me.chanjar.weixin.common.api.WxMessageInMemoryDuplicateChecker}
	 * </pre>
	 * @param messageDuplicateChecker
	 */
	public void setMessageDuplicateChecker(WxMessageDuplicateChecker messageDuplicateChecker) {
		this.messageDuplicateChecker = messageDuplicateChecker;
	}

	/**
	 * <pre>
	 * 设置自定义的{@link me.chanjar.weixin.common.session.WxSessionManager}
	 * 如果不调用该方法，默认使用 {@link me.chanjar.weixin.common.session.StandardSessionManager}
	 * </pre>
	 * @param sessionManager
	 */
	public void setSessionManager(WxSessionManager sessionManager) {
		this.sessionManager = sessionManager;
	}

	/**
	 * <pre>
	 * 设置自定义的{@link me.chanjar.weixin.common.api.WxErrorExceptionHandler}
	 * 如果不调用该方法，默认使用 {@link me.chanjar.weixin.common.util.LogExceptionHandler}
	 * </pre>
	 * @param exceptionHandler
	 */
	public void setExceptionHandler(WxErrorExceptionHandler exceptionHandler) {
		this.exceptionHandler = exceptionHandler;
	}

	List<WxMpMessageRouterRule> getRules() {
		return this.rules;
	}

	/**
	 * 开始一个新的Route规则
	 * @return
	 */
	public WxMpMessageRouterRule rule() {
		return new WxMpMessageRouterRule(this);
	}

	/**
	 * 处理微信消息
	 * @param wxMessage
	 */
	public WxMpXmlOutMessage route(final WxMpXmlMessage wxMessage) {
		if (isDuplicateMessage(wxMessage)) {
			// 如果是重复消息，那么就不做处理
			return null;
		}

		final List<WxMpMessageRouterRule> matchRules = new ArrayList<WxMpMessageRouterRule>();
		// 收集匹配的规则
		for (final WxMpMessageRouterRule rule : rules) {
			if (rule.test(wxMessage)) {
				matchRules.add(rule);
				if (!rule.isReEnter()) {
					break;
				}
			}
		}

		if (matchRules.size() == 0) {
			return null;
		}

		WxMpXmlOutMessage res = null;
		@SuppressWarnings("rawtypes")
		final List<Future> futures = new ArrayList<Future>();
		for (final WxMpMessageRouterRule rule : matchRules) {
			// 返回最后一个非异步的rule的执行结果
			if (rule.isAsync()) {
				futures.add(executorService.submit(new Runnable() {
					public void run() {
						rule.service(wxMessage, wxMpService, sessionManager, exceptionHandler);
					}
				}));
			} else {
				res = rule.service(wxMessage, wxMpService, sessionManager, exceptionHandler);
				// 在同步操作结束，session访问结束
				log.debug("End session access: async=false, sessionId={}", wxMessage.getFromUserName());
				sessionEndAccess(wxMessage);
			}
		}

		if (futures.size() > 0) {
			executorService.submit(new Runnable() {

				public void run() {
					for (@SuppressWarnings("rawtypes") Future future : futures) {
						try {
							future.get();
							log.debug("End session access: async=true, sessionId={}", wxMessage.getFromUserName());
							// 异步操作结束，session访问结束
							sessionEndAccess(wxMessage);
						} catch (InterruptedException e) {
							log.error("Error happened when wait task finish", e);
						} catch (ExecutionException e) {
							log.error("Error happened when wait task finish", e);
						}
					}
				}
			});
		}
		return res;
	}

	protected boolean isDuplicateMessage(WxMpXmlMessage wxMessage) {

		String messageId = "";
		if (wxMessage.getMsgId() == null) {
			messageId = String.valueOf(wxMessage.getCreateTime()) + "-" + wxMessage.getFromUserName() + "-" + String.valueOf(wxMessage.getEventKey() == null ? "" : wxMessage.getEventKey()) + "-"
					+ String.valueOf(wxMessage.getEvent() == null ? "" : wxMessage.getEvent());
		} else {
			messageId = String.valueOf(wxMessage.getMsgId());
		}

		if (messageDuplicateChecker.isDuplicate(messageId)) {
			return true;
		}
		return false;

	}

	/**
	 * 对session的访问结束
	 * @param wxMessage
	 */
	protected void sessionEndAccess(WxMpXmlMessage wxMessage) {

		InternalSession session = ((InternalSessionManager) sessionManager).findSession(wxMessage.getFromUserName());
		if (session != null) {
			session.endAccess();
		}

	}
}
